Search results for "Lidar"
showing 10 items of 475 documents
TOF LiDAR with SiPM technology
2016
LiDAR (Light Detection And Ranging) systems measures the distance from the sensor to the target by determining the time between the release of the laser pulse to the receiving of the backscattered pulse. The interest in LiDAR technology has exploded in recent years since the applications are numerous. Here, we would highlight the Advanced Driver Assistance Systems (ADAS) and for rendezvous & docking operations between spacecraft. We built two LiDAR systems differing for the detector: a Silicon Photomultiplier (SiPM) and an Avalanche Photodiode (APD). The advantages of the SiPM approach has been extensively discussed in [1]. The comparison between these systems has been performed in terms of…
Comparison in terms of TOF measurements between APD and SiPM for LiDAR applications
2016
We present an experimental comparison of two LiDAR systems, employing the SiPM and the APD as photodetectors, in terms of TOF measurements differing for the distance of the target and at different intensities of ambient light. The use of the APD represents the conventional approach, while the implementation of the SiPM is innovative. The performed measurements achieved very promising results, thus demonstrating the effectiveness of our LiDAR based on SiPM.
Topogrāfisko karšu pārveide uz 3D modeli un to izmantošana
2020
Bakalaura darba ietvaros tiks pētīts risinājums, kā no topogrāfisku karšu datiem var iegūt izmantojamu, 3D reprezentāciju, kas pēc tam varētu noderēt vairāku jomu pārstāvjiem, piemēram, spēļu izstrādātājiem, pilsētu plānotājiem vai arī cilvēkiem, kas to grib darīt hobija līmenī. Kursa darba ietvaros tika pētīta šī datu pārveide, tika atrasts veids, kā no LiDAR datiem var iegūt izmantojamu 3D modeli, taču tas, ko var izdarīt tālāk ar šiem modeļiem netika tik plaši apskatīts. Šajā bakalaura darbā tika izvirzīti vairāki mērķi – parādīt, ka ir iespējams iegūt 3D modeļus no LiDAR datiem vairākos veidos, aprakstīt, kur mūsdienās tiek izmantoti šāda veida 3D modeļi, izveidot divus spēļu prototipus…
Apport de la topographie par LiDAR aéroporté à la caractérisation volumique et spatiale d’amas de déchets sidérurgiques. L’exemple des ateliers de Mo…
2022
Parmi les grands districts de production de fer brut connus, la Puisaye (Bourgogne du nord – Yonne et Nièvre) figure parmi les plus importants à l’échelle métropolitaine, si ce n’est à l’échelle européenne. Plus de 2500 amas de déchets, marquant l’emplacement d’ateliers de réduction du minerai de fer, sont ainsi connus en prospections (Piétak et al. 2012). Les résultats des travaux engagés depuis 2017 dans le cadre d’un Projet Collectif de Recherche, financé par la DRAC Bourgogne-Franche-Comté et le CNRS, ont permis de révéler la continuité de ces activités de production du fer depuis le premier âge du fer jusqu’au second Moyen âge. Pour la période antique, ces amas de déchets se caractéris…
Optimizing the Sampling Area across an Old-Growth Forest via UAV-Borne Laser Scanning, GNSS, and Radial Surveying
2022
Aboveground biomass, volume, and basal area are among the most important structural attributes in forestry. Direct measurements are cost-intensive and time-consuming, especially for old-growth forests exhibiting a complex structure over a rugged topography. We defined a methodology to optimize the plot size and the (total) sampling area, allowing for structural attributes with a tolerable error to be estimated. The plot size was assessed by analyzing the semivariogram of a CHM model derived via UAV laser scanning, while the sampling area was based on the calculation of the absolute relative error as a function of allometric relationships. The allometric relationships allowed the structural …
Telpas punktu mākoņa ieguve un apstrāde
2016
Darbā “Telpas punktu mākoņa ieguve un apstrāde” tika pētīti dažādu telpas punktu mākoņu ieguves veidi un tālākā datu apstrāde. Darba ietvaros tika aplūkoti vairāki datu iegūšanas veidi, identificētas katra veida pielietojuma iespējas, priekšrocības,trūkumi un veikts uz eksperimentiem balstīts ātrdarbības novērtējums. Veikts dažādu pastāvošu risinājumu salīdzinājums. Aplūkoti galvenie datu pēcapstrādes virzieni, salīdzināti datu glabāšanas risinājumi un piedāvāts autora ieteikums punktu kvalitātes novērtēšanā. Darba ietvaros tika veikti praktiski eksperimenti, kuru mērķis bija iegūt vairākus apkārtējās vides punktu mākoņus, izmantojot dažādus datu ieguves veidus. Autors darba izstrādes gaitā…
Determination of the vertical distribution of aerosols in Valencia, Spain, by means of lidar measurements
2017
La Tierra atraviesa un proceso de cambio climático caracterizado por un aumento de la temperatura media del planeta. Este calentamiento es debido en gran parte al aumento de la concentración de gases de efecto invernadero derivado de las actividades humanas. No obstante, existen otros componentes atmosféricos que pueden afectar de manera significativa el balance radiativo de la Tierra. Uno de estos componentes son los aerosoles, partículas que se encuentran en suspensión en la atmósfera. Según el informe del Panel Intergubernamental sobre el Cambio Climático (IPPC) del año 2013, el efecto neto de los aerosoles sobre la temperatura media del planeta es de enfriamiento. Sin embargo, estas est…
Vertical profiling of Saharan dust with Raman lidars and airborne HSRL in southern Morocco during SAMUM
2009
Three groundâÂ�Â�based Raman lidars and an airborne highâÂ�Â�spectralâÂ�Â�resolution lidar (HSRL) were operated during SAMUM 2006 in southern Morocco to measure height profiles of the volume extinction coefficient, the extinctionâÂ�Â�toâÂ�Â�backscatter ratio, and the depolarization ratio of dust particles in the Saharan dust layer at several wavelengths. Aerosol Robotic Network (AERONET) Sun photometer observations and radiosounding of meteorological parameters complemented the groundâÂ�Â�based activities at the SAMUM station of Ouarzazate. Four case studies are presented. Two case studies deal with the comparison of observations of the three groundâÂ�Â�based lidars during a heavy du…
Dust mobilization and transport in the northern Sahara during SAMUM 2006 – a meteorological overview
2009
The SAMUM field campaign in southern Morocco in May/June 2006 provides valuable data to study the emission, and the horizontal and vertical transports of mineral dust in the Northern Sahara. Radiosonde and lidar observations show differential advection of air masses with different characteristics during stable nighttime conditions and up to 5-km deep vertical mixing in the strongly convective boundary layer during the day. Lagrangian and synoptic analyses of selected dust periods point to a topographic channel from western Tunisia to central Algeria as a dust source region. Significant emission events are related to cold surges from the Mediterranean in association with eastward passing upp…
A Survey on Sensors for Autonomous Systems
2020
This paper presents a survey on state-of-the-art sensors for autonomous systems. The key performance parameters along with the operating principle of sensors used in autonomous systems are thoroughly explored. Practical aspects such as performance parameters, sensor output data format, sensor interfaces, size, power consumption, compatible hardware platforms, data analysis, and signal processing complexities are summarized. Such information serves as a practical guide for designing smart sensing systems for autonomous systems.